combustion and flame class 8

Rapid combustion is

• When gas burns, it produces heat & light

• When material suddenly burst into flames

• When there is evolution of heat

• None of these

Which is the hottest part in flame of candle ?

• Blue (outer)

• Yellow (middle)

• Black (inner)

• Wax part

Substance that does not burn in air is

• Sand

• Kerosene

• Wood

• Diesel

The amount of heat energy produced on complete combustion of 1 kg of fuel is called

• Calorific value

• Significant value

• Heat value

• Internal value

Bursting of crackers is an example of

• Rapid combustion

• spontaneous combustion

• Explosion

• All of these

There are following zones of flame

• Two

• Four

• Three

• No zone

Cutting off trees at large scale leads to

• Deforestation

• Afforestation

• Reforestation

• Both deforestation & afforestation

The acronym for putting out a fire using a fire extinguisher is PASS . What does PASS stands for

• Pull, aim, squeeze, spread

• Pul, accuracy, squeeze, spread

• Pin, aim, squeeze, sweep

• Pull, aim, squeeze, sweep

Substance which catch fire are called

• Acids

• Bases

• Burners

• Combustible

CNG & LPG are examples of

• Solid fuels

• Liquid fuels

• Gaseous fuels

• They are not fuels